Re: ini questions

[Ray <rehenry-at-up.net>]

Ronald

(comments and questions mixed in)

On Wed, 30 May 2001,   "Ronald J Heaps/RJH/CC01/INEEL/US"
<RJH-at-inel.gov>wrote: > 

I have a couple of questions. I want to set up EMC to control a lathe type 
> machine. I control servo motors using step/direction output. One of the 
> motors is to run the rotating axis one runs a sliding table. How do you set 
> the soft limit for the rotating axis so there is none? I want to be able to 
> rotate without worrying about hitting a limit.. 

Spindle is normally a velocity control rather than a position control. 
There are many lathes that also define spindle as C if they are using live
tooling.   You'd have to go into the source to disable limits but I'd think
that you could set it very large.  

IMHO - It is at this point that we need a third axis type definition,
"rotary."  In my imagination a rotary axis would reset itself to zero each
time it crossed the zero point or hit an index pulse or something like that.

There was some discussion of this in the source documentation and it was
decided to define angular as wrapped linear.

> The other question also has to do with the ini file. I want to know what to
> set so the sliding table moves the distance I want and the display also
> reflects the distance. From reading the manual, it seems the input_scale is
> the variable to adjust. When I adjust this it does not always make sense. I
> tried calculating the number as it is shown and it causes tkemc to be a bit
> jumpy as the mouse moves around, and the distance of the move is not
> correct. If I set it at "1,000   0" everything moves smoothly but when I am
> in mdi mode and tell it to move 1 inch, the reading says 1.000 but the
> actual move is about 1/10". If I set input_scale to "10,000  0" and tell it
> to move 1 inch, the readout is 1.000 and the actual move is about 2.5/10".
> I get that jumpy mouse move as well. It also seems to change the speed at
> which the motor turns. What is happening, what am I doing wrong?

What number did you calculate to be correct?

I really don't understand what is happening here.  Tkemc with a jumpy
mouse pointer almost sounds like a freqmod period type problem but it
shouldn't vary with the number of steps per unit.   Are you using freqmod? 

I'd be happy to look at the different ini's that you are trying.  You can
attach them to a message to me.  I can get back to you sometime this
evening.

Now to set the input scale I'd first use the incremental manual jog buttons
rather than MDI.  If you do use MDI be certain to issue a G20 first so that
you know you are in inch mode.  There were several releases where
g21 was the default and reset value.  Something like g20 g0 x1 should do
it.  Repeat the g20 each time because abort, reset. and such may switch it
back. 

There is a fix for this in the newer code.  You can put a line in the
General section [EMC] of your ini file like this.

; Startup codes for RS-274-NGC interpreter
RS274NGC_STARTUP_CODE =	G20

If this works on your release, you will see a g20 rather than a g21 in the
line of m and g codes just below the mdi input line.

Now that you are certain that you are commanding the inch move, you should
be able to adjust the input scale for the correct number of steps per inch.

For a minute let me assume that you are commanding mm rather than inches. 
If you get 0.25" with 10000 as your input value, then you should get 6.35"
if you were commanding inches and using 10000.  If this were correct, then
an input value of 1575 should be about right.

HTH  And get back to us.

Ray